This invention relates to air mixing apparatus that is particularly useful in connection with a winter make-up air and a summer ventilation system for a factory, warehouse or the like.
Ventilation and air circulating systems for buildings are well known. Reference may be made, for example, to the following U.S. Pat. Nos.: 3,691,928 issued Sept. 19, 1972; 3,404,618 issued Oct. 8, 1968; 3,446,272 issued May 27, 1969; 3,474,720 issued Oct. 28, 1969; 3,747,501 issued July 24, 1973 and 3,524,399 issued Aug. 18, 1970.
Generally speaking, such ventilation and air circulation systems include some form of air mixing apparatus that is capable of drawing air from both inside the building and outside of the building and a duct that is suspended from the roof of the building and which is connected to the air mixing apparatus to receive air therefrom. The duct has a plurality of outlets along its length. Air at an appropriate temperature, which depends upon the ratio of outside and inside air that is drawn into the air mixing apparatus, is forced into the duct and exits from the duct in the area of the roof of the building. The result is that smoke and fumes are diluted, stratification of heat and foul air is eliminated, and air quality and temperature are homogenized from floor to ceiling. The system is energy efficient, since waste heat adjacent the roof area is forced down to the floor area. Another advantage of the system is that the drawing in of fresh make-up air eliminates negative pressure and stops the infiltration of cold outside air and therefore drafts and cold spots.
A typical type of air mixing apparatus which has been used in the past is shown in aforementioned U.S. Pat. No. 3,691,928. It is subject to a number of disadvantages. More specifically, the system shown therein is difficult to balance, is subject to mechanical failure, and the dampers and operating linkage therefor can freeze up during the winter.
Two different types of air mixing apparatus are shown in U.S. Pat. No. 2,313,676 issued Mar. 9, 1943 and U.S. Pat. No. 2,896,849 issued Jul. 28, 1959. The disadvantage of the apparatus shown in U.S. Pat. No. 2,896,849 is that it is relatively complex and requires separate cold air and warm air ducts. The apparatus shown in U.S. Pat. No. 2,313,676 also is relatively complex and requires two separate mechanisms for controlling the ratio of outside air to recirculating inside air.
The prior art noted hereinbefore is the most relevant prior art known to the inventor and assignee of the instant application.